Moved event stuff to a non-manager NS.

Core assembly concept: Assemblies that will never need to get unloaded (Torch.API, Torch, Torch.Server)
Event shims and patch shims on the core assemblies.

Torch.API/Event/IEvent.cs

@@ -0,0 +1,11 @@
+namespace Torch.API.Event
+{
+    public interface IEvent
+    {
+        /// <summary>
+        /// An event that has been cancelled will no be processed in the default manner.
+        /// </summary>
+        /// <seealso cref="EventHandlerAttribute.SkipCancelled"/>
+        bool Cancelled { get; }
+    }
+}